ES2831503T3 - Improved autoinjector that supports the syringe in the front - Google Patents

Abstract

An autoinjector comprising a housing in which a syringe can be mounted comprising: a barrel for containing a volume of drug, a needle (10) at one end of the barrel in fluid communication with the drug, an axially movable plunger in the barrel to a more forward position; a needle sheath (16) that is capable of sealing the forward most end of the needle to maintain the sterility of the medication within the cylinder whereby, in use, the needle sheath must be removed from the needle immediately prior to actuating the autoinjector; and a removable needle cover (17) for containing the needle cover (16); The autoinjector comprises: a syringe support means (100, 100 ') for supporting the barrel of the syringe at an axial location at or ahead of the forward most position of the syringe plunger, the means (100, 100') of Syringe holder provides a reaction surface (109, 109 ') for a forward shoulder of the barrel or a narrow cone region of the syringe where the needle is attached; characterized in that said syringe support means (100, 100 ') comprises an intermediate portion (105) and a front portion which together include radially spaced grooves (107) defining a plurality of radially flexible fingers (108, 108'), the The plurality of radially flexible fingers (108, 108 ') comprise one or more inwardly directed protrusions that form said reaction surface, wherein the reaction surface (109, 109') is configured to provide an axial compressive force on the syringe barrel when a forward axial force is applied to the syringe plunger, and wherein when the syringe is inserted into the syringe support means (100, 100 '), the fingers (108, 108') radially Flexible flexes flex radially outward from a normal position as a needle cover (17) passes and then the spring returns to its normal position.

Description

DESCRIPTION

Improved autoinjector that supports the syringe in the front

This invention relates to the field of autoinjectors for the administration of liquid medicament, for example, interferon.

Background

An autoinjector is an automatic injection device designed to facilitate the automatic delivery of a dose of medication to a patient through a hypodermic needle, the injection is normally administered by the patient himself. An autoinjector works, for example, by delivering an injection automatically when actuated by the patient by pressing a button, moving a lever or part of a housing, etc. This is in contrast to a conventional manual syringe where the patient himself needs to directly press a plunger into a cylinder containing medication to effect the injection. The terms "autoinjector" and "injection device" are used interchangeably in the following description.

Examples of autoinjectors are described in WO2003 / 099358 (Seedlings Life Science Ventures LLC) and WO01 / 93926 (Mayo Foundation for Medical Education and Research). Both are generally flat devices that are small in size to encourage users to carry the device with them for easy access. GB2396298 (PA Consulting Services Ltd) is an example of an elongated autoinjector of more conventional shape, but relatively complex internal construction.

All three of the prior art devices have a custom designed medication chamber within them rather than being built around a standard pre-filled syringe presentation. The custom medication chamber, while allowing for a compact overall size for the device, means that the device as a whole must be subject to more rigorous regulatory scrutiny compared to a device that contains a standard pre-filled syringe presentation that will have already achieved the regulatory approval.

Another reason that the prior art cannot be used in conjunction with a standard syringe presentation is related to the needle. Typically, a standard pre-filled syringe presentation, for use within a disposable autoinjector, includes a needle in communication with a medication chamber contained within the syringe barrel. It is essential that the sterility and integrity of the needle are maintained and protected until the moment the injection is required. This is generally accomplished by providing a needle cover that comprises a solid sheath (eg, an elastomer such as rubber) in which the needle is pricked or poked so that it is surrounded and sealed on all sides. Usually at least the front 3-4mm of the needle is embedded in the rubber of the needle cover. The autoinjector cannot be operated with the needle cover attached. Immediately prior to actuation of the device, the user removes the needle cover, for example, by removing an end cap from the device to which the needle cover is attached, so that the needle is ready for use. In contrast, WO01 / 93926, for example, has a completely different type of needle sleeve 79 that is designed to be broken by the needle moving forward during use of the autoinjector. In other words, this type of breakable needle cover does not need to be removed from the device prior to actuation; however, such needle covers are likely to provide less mechanical protection than those provided in a standard pre-filled syringe presentation and generally do not directly maintain drug and needle sterility.

Generally, an autoinjector includes a needle that is located within the housing of the device. Upon activation of a force-generating source, a portion of the needle extends out of the housing and penetrates the outer skin layer to deliver the drug. In some known autoinjectors, after activation, a needle cover or needle shield is moved forward to hide the needle after use. In GB2396298, the needle is automatically retracted into the housing by a tilt spring.

An improved autoinjector is described in our pending international patent application, published under number WO 2005/070481. Some of the reference numbers of the present application correspond to the equivalent components of the device described in WO 2005/070481. This device requires the needle to move axially so that it can appear beyond the end of the nozzle for the duration of the injection, after which the needle is automatically retracted, so that it is never in view of the user. The device also requires the plunger to move axially for the drug to be expelled. The overall complexity of the autoinjector is significantly reduced because both requirements are affected by one component, namely an internal housing, and the device has the significant advantage that it can be built around a conventional or standard syringe presentation.

The injection device of WO 2005/070481 is designed to be used in conjunction with a standard drug presentation, for example, a pre-filled syringe comprising a needle, a barrel pre-filled with medication, and a plunger. The plunger may include a separately provided plunger rod. As mentioned above, there is a significant business advantage to being able to use a pre-filled syringe standard, which will have undergone numerous clinical trials, drug stability studies, and regulatory approval. Any modification to the standard syringe may require additional testing and approval, adding to delay and expense. The present invention is relevant to any injection device to be used in conjunction with a standard pre-filled syringe presentation (whether pre-filled or not and either single-use or reusable), not just the device described in WO 2005/070481.

The barrel of a syringe is usually made of glass, since glass has the most favorable storage properties for many drugs. However, glass is notoriously brittle and there is a risk of damage or breakage of the syringe during injection if the forces to which the syringe is subjected by the injection device are not adequately controlled. This is particularly so when the liquid medicine is relatively viscous, requiring a greater force to expel it from the syringe through the needle. Cylinders made of materials other than glass, for example polyethylene or cyclic olefin polymers, are less brittle when subjected to normal forces during injection, but would still benefit from the invention described below.

In the known device described in our pending patent application No. WO 2005/070481 and illustrated in Figures 1-3 of the present application, the syringe is supported within the injection device by a syringe barrel or holder 9. The syringe holder 9 comprises an elongated housing that closely surrounds the glass barrel of the syringe. The annular rim 90 at the rear of the syringe barrel rests on a barrel seat 91 at the rear of the syringe holder 9. The annular lip 90 on the back of the syringe barrel is often referred to as the "finger lip" because, during a conventional (manual) injection using a syringe, the user's index and middle fingers naturally rest in front of the "finger lip. ”To provide the necessary resistance to allow the plunger to be depressed with the thumb to deliver the medication.

The seat of the barrel, for example, in the form of an annular rim, preferably prevents forward axial movement of the syringe relative to the syringe holder, so that, in use, the syringe barrel and the syringe holder move axially. together as a unit.

In use, as described in WO 2005/070481, there are three stages of delivering an injection. Before giving an injection (referring to Figure 1 of the present application), the end cap 15 is removed, by removing the needle cover 17 (if present) and the rubber needle cover 16 with it from the needle. In the first stage of delivering an injection, as shown in Figure 2 of the present application, the labels 7B at the front end of the inner housing 7 are in contact with the syringe barrel 90, which is pushed axially forward ( taking the syringe holder 9 with it), so that the needle 10, which is attached to the front end of the cylinder, moves in the direction indicated by the arrow so that it finally protrudes from the nozzle 11 at the front of the device . The forward travel of the barrel and the syringe holder is limited when a surface 9A of the syringe holder reaches a stop 11A within the nozzle or the front housing 11.

Referring now to Figure 3, the second stage of injection is drug delivery in which the labels 7A on the rear of the inner housing 7 press the plunger 8 into the syringe barrel. During this stage, the syringe barrel is held axially stationary, by bearing the annular shoulder 90 of the "finger" against the barrel seat 91, which results in the barrel being placed in tension when the plunger pushes the liquid medication. non-compressible towards the front end of the cylinder. This tension is undesirable in a glass cylinder, which can be damaged or broken, especially if the medicine comprises a particularly viscous liquid that requires greater force to expel it from the syringe through the needle. Viscous medications are desirable in certain applications, where the use of a sustained release viscous medication reduces the frequency with which an injection is required.

It is desirable to minimize the diameter of the needle as much as possible, because the smaller the diameter of the needle, the less painful the resulting injection. However, for a given needle length, the smaller the diameter of the needle, the greater the force required to eject the drug from the syringe.

It is also desirable to minimize the duration of the injection, that is, to maximize the rate at which the drug is delivered from the syringe. Particularly when the diameter of the needle is small, minimizing the duration of the injection also means an increase in the force used to expel the drug from the syringe.

Consequently, increased forces on the syringe increase the likelihood that the syringe will break during injection. The risk of the syringe breaking during injection is significant and is not only inconvenient and expensive, but it is also potentially dangerous. If broken, shards of glass and / or the needle may dislodge and come out of the front of the device, causing injury. Additionally, there is a risk that the remaining drug will leak or be expelled from the device in an uncontrolled manner, potentially delivering the wrong dose to the patient or causing injury, for example if the drug comes into contact with the patient's skin or eyes. These problems are amplified when the drug is viscous, since in such applications a more powerful source of energy is needed, so that the forces involved are greater. It is known that a typical syringe breakage would occur during injection at the finger rim, whereby the finger rim 90 on the syringe barrel breaks as a result of its bearing against the barrel seat 91. Therefore, it is highly desirable to minimize the likelihood of syringe breakage.

In the third stage of injection (not illustrated in the present application, but shown in WO 2005/070481), once the medicine has been delivered and the internal housing 7 is no longer in contact with the cylinder or piston of the syringe, the secondary spring 12 biases the syringe holder (and therefore the syringe contained therein) axially rearward to retract the syringe back into the housing so that the used needle is hidden from view.

WO2005115507 discloses an autoinjector with a syringe support means that provides a reaction surface to the forward end of the barrel.

Summary of the invention

The present invention is defined in the appended claims. According to a first aspect, there is provided an autoinjector comprising a housing in which a syringe comprising

a cylinder to hold a volume of medicine,

a needle at one end of the barrel in fluid communication with the drug,

an axially movable plunger in the cylinder to a forward most position;

a needle cover that is capable of sealing the forward most end of the needle to maintain the sterility of the drug within the barrel whereby, in use, the needle cover must be removed from the needle immediately prior to actuation of the autoinjector; and a removable needle cover to contain the needle cover;

the autoinjector comprises:

a syringe support means for supporting the syringe barrel in an axial location at or forward of the forward most position of the syringe plunger, the syringe support means provides a reaction surface for a front shoulder of the barrel or a narrow cone region of the syringe where the needle is attached, characterized in that said syringe support means comprises an intermediate portion and a front portion which together include radially spaced grooves defining the plurality of radially flexible fingers, the plurality of radially flexible fingers comprises one or more inwardly directed protrusions that form said reaction surface, wherein the reaction surface is configured to provide an axial compressive force on the barrel of a mounted syringe when a forward axial force is applied to the plunger of the assembled syringe, and wherein when the syringe is inserted into the syringe support means, the radially flexible fingers flex radially outward from a normal position when a needle cover passes and then the spring returns to its normal position.

Preferably the autoinjector is a single use autoinjector. The simple construction of the autoinjector makes it well suited for applications such as emergency use to inject a large population to control a pandemic, where a large number of cost-effective disposable autoinjectors are required. A single-use autoinjector also provides a very convenient means for patients to administer their own injections, even if they lack dexterity and / or clinical experience. The delivery of viscous drugs is particularly problematic for patients who lack dexterity due to the increased force required to administer such drugs, a problem that is alleviated by the present invention.

Typically, the autoinjector contains a power source, for example a coil spring, to move the plunger axially in the cylinder to deliver an injection in less than 30 seconds.

Preferably, the syringe is axially movable in said housing and is inclined such that the needle is normally completely inside said housing, wherein prior to injection the syringe can be moved axially in order to move at least a part of said needle. outside the housing and in which after injection, the syringe is capable of retracting in order to retract said part of said needle in the housing. The concealment of the needle both before and after injection makes the autoinjector especially suitable when the patient has some aversion to needle injection. Retraction and retention of the needle after injection eliminates the risk of needle sticks.

According to another aspect there is provided a method for assembling an autoinjector comprising the steps of:

providing a first partial assembly comprising a front housing and a tightly fitting end cap;

providing a second assembly comprising a rear portion of the autoinjector;

providing a syringe comprising a barrel for containing a volume of drug, a needle at one end of the barrel, and an axially movable plunger in the barrel to a forward most position;

providing a syringe support means;

inserting the syringe axially into the rear end of the syringe support means until said syringe support means supports the syringe;

inserting the forward end of said syringe and syringe support means into said first partial assembly; assembling said first partial assembly and second assembly together such that said syringe support means supports the syringe in an axial location at or ahead of the most forward position of the plunger, whereby in Using said reaction surface provides an axial compressive force on said cylinder when a forward axial force is applied to the plunger.

According to another aspect there is provided a method for assembling an autoinjector comprising the steps of:

providing a first partial assembly comprising a syringe support means, the syringe support means provides a reaction surface for a front shoulder of a barrel or a narrow cone region of a syringe where a needle is attached, a front housing and a tightly fitting end cap; wherein said syringe support means comprises an intermediate portion and a front portion which together include radially spaced grooves defining a plurality of radially flexible fingers, the plurality of radially flexible fingers comprising one or more inwardly directed protrusions forming said surface reaction; Y

providing a second assembly comprising a rear portion of the autoinjector;

providing a syringe comprising a barrel for containing a volume of medicine, a needle at one end of the barrel; an axially movable plunger in the cylinder to a forward most position; and a removable needle cover to contain a needle cover that is capable of sealing the forward most end of the needle to maintain the sterility of the medication within the barrel, whereby in use, the needle cover must be removed from the needle immediately before activating the autoinjector;

inserting the syringe axially into the rear end of the first partial assembly until said syringe support means supports the syringe; Y

assembling said first partial assembly and second assembly together such that said syringe support means supports the syringe in an axial location at or forward of the most forward position of the plunger, whereby in use said reaction surface provides a force of axial compression on said cylinder when a forward axial force is applied to the plunger; and wherein when the syringe is inserted into the syringe support means, the radially flexible fingers flex radially outward from a normal position as the needle cover passes and then the spring returns to its normal position.

Additional features of the invention are defined in the appended claims.

Brief description of the drawings

The preferred embodiments of the present invention will now be described more particularly, by way of example only, with reference to the accompanying drawings in which:

Figure 1 (PRIOR ART) is a perspective view of a known injection device;

Figure 2 (PRIOR ART) is a plan view, partially in section of the device of Figure 1, with the cap and needle cover removed, ready for actuation;

Figure 3 (PRIOR ART) is a plan view, partially in section of the device of Figure 1, with the needle exposed, ready to depress the plunger to deliver the medication;

Figure 4 is a perspective view of an injection device incorporating one aspect of the present invention;

Figure 5 is a plan view, partially in section of the device of Figure 4, with the cap, needle cover and needle cover removed, ready for actuation;

Figure 6 is a plan view, partially in section, of the device of Figure 4, with the needle exposed, ready to depress the plunger to deliver medication;

Figure 7 is a perspective view of the syringe holder;

Figure 8 is a cross-sectional view of the syringe holder of Figure 7;

Figure 9 is a cross-sectional view of the syringe holder of Figure 7, showing a syringe in place;

Figure 10 is a cross-sectional view of the syringe holder of Figure 7, showing a syringe, needle cover, and needle cover in place;

Figure 11 shows a detail, drawn on a larger scale, of the interface between the front of the glass syringe barrel and the syringe holder illustrated in Figure 10;

Figure 12, drawn to a larger scale, is a cross-sectional view of the modified front casing; Figure 13, drawn to a larger scale, is a cross-sectional perspective view of the front housing;

Figure 14 is a cross-sectional view of the front housing, cap, and syringe holder assembled together;

Figure 15 is a perspective view of the front housing, cap, and syringe holder assembled together;

Figure 16 is a cross-sectional view of the front housing, cap, syringe holder, and syringe assembled together;

Figure 17 is a cross-sectional view of an alternative embodiment of the syringe holder;

Figure 18 is a partial assembly view showing the syringe holder of Figure 17 together with its spring retainer, a syringe therein, and the end cap and front housing;

Figure 19 shows the partial assembly of Figure 18 with the needle cover removed;

Figure 20 is a perspective view of the syringe holder of Figure 17 together with its spring retainer;

Figure 21 is a perspective view of a syringe holder, end cap and front housing, showing an alternative means for retaining the gripping means against the syringe barrel.

Figure 22 is a perspective view of another embodiment of the syringe holder in conjunction with a needle cover.

Detailed description

Throughout the description and claims of this specification, the words "comprise" and "contain" and variations of the words, for example "comprising" and "comprises", mean "including, but not limited to" , and is not intended for (and does not exclude) other components, integers or stages.

Throughout the description and claims of this specification, the singular encompasses the plural unless the context requires otherwise. In particular, when the indefinite article is used, it should be understood that the specification contemplates both plurality and singularity, unless the context requires otherwise.

Throughout the following description, reference to a "forward" direction means the direction that is toward the patient when the injection device is in use. The "forward" end of the injection device is the end closest to the patient's skin when the device is in use. Similarly, reference to a "rearward" direction means the direction that is away from the patient and the "rearward" end of the device is the end furthest from the patient's skin when the injection device is in use.

The "plunger" includes any elastomeric plug or the like that seals the chamber containing the liquid medication. The plunger also typically includes a plunger rod, but this may be provided separately from the elastomeric plug and need not be an essential part of the syringe. The "forward most position" of the plunger refers to the forward most position of any part of the plunger (usually the most forward edge of the plug).

The functions, integers, characteristics or groups described in conjunction with a particular aspect, embodiment or example of the invention are to be understood as applicable to any other aspect, embodiment or example described herein unless it is incompatible therewith.

As described above, a disadvantage of the known prior art is that the syringe barrel is placed in tension when the plunger pushes the non-compressible liquid drug toward the forward end of the delivery barrel. This tension is undesirable in a glass cylinder, which can be damaged or broken, especially if the medicine comprises a particularly viscous liquid that requires greater force to expel it from the syringe. There is a possibility that the glass syringe will break in the fingertip region as a result of the forces it is subjected to during delivery of an injection. One way to mitigate this problem is to reduce the effect of those forces in the toe flange region. For example, the syringe holder of WO 2005/070481 can be modified by providing a helical groove at the rear end thereof which, in use, provides elasticity to the cylinder seat region in which the finger flange is located. syringe (not illustrated). The elastic flex absorbs shock and reduces the risk of syringe breakage in the fingertip region.

Other means may be envisaged to reduce the effect of forces in the fingertip region, for example, by providing an O-ring shaped cushion or molding a relatively soft or elastomeric material into a harder substrate in the region of the finger. cylinder seat.

It is known that a typical syringe breakage would occur during injection at the finger rim, whereby the finger rim 90 on the syringe barrel breaks as a result of its bearing against the barrel seat 91. However, the Applicant has recognized that it is also possible that the syringe may break at points on the barrel in front of the finger edge. This is potentially more serious as larger straight glass shards can be ejected from the front of the device, as well as the unsecured needle, and any remaining medication will leak out uncontrollably.

The risk of breakage or damage to the glass syringe can be reduced by ensuring that the barrel remains in compression during drug delivery (stage two of the injection process described in WO 2005/070481), rather than being in tension. This can be accomplished by supporting the forward end of the barrel and having a reaction surface in which an axial compressive force can be applied to the barrel when a forward axial force is applied to the plunger during drug delivery.

In the injection device of the present invention, the conventional syringe holder 9 is replaced by a more complex syringe holder that is capable of supporting the syringe at the front end of its barrel rather than at its rear flange 90 during delivery. of the medicine. In the embodiment described below, the syringe holder supports the syringe on the front shoulder of its barrel and provides a reaction surface there for the front shoulder of the barrel. By "front shoulder" is meant the region where the largest diameter of the cylinder is reduced to a smaller diameter at the nozzle. The forward shoulder 92 is indicated in Figure 9. Alternatively, the syringe could be supported and the reaction surface provided in the narrow "cone" where the needle is attached thereto and these embodiments are described in more detail below. The syringe may, in fact, rest anywhere on the barrel that, in use, is forward of the forward most position of the fully depressed syringe plunger and where a reaction surface can be provided for the syringe (so that the barrel remains in compression during drug delivery).

However, the desired support or clamping of the barrel by the syringe holder at its forward end presents an assembly difficulty for a product in which it is desired to keep manufacturing and assembly costs to a minimum. In the prior art device, the syringe can simply be dropped onto the rear end of the syringe holder until its lip 90 rests on the seat 91 of the barrel. This determines the axial position of the syringe relative to the syringe holder. In practice, the prior art syringe holder is supplied assembled with the front of the device, so that the pre-filled syringe can simply be placed in the syringe holder and then the front of the device (which includes syringe) to the already assembled back of the device in a simple two-stage assembly operation.

In the present invention, it is not possible to use the finger flange 90 and the barrel seat to determine the axial position of the syringe relative to the syringe holder. This is because the syringe holder needs to actively support the syringe at its forward end (preferably at the forward shoulder 92 of the glass barrel). In the preferred embodiment, there are inwardly directed gripping means to retain the forward shoulder of the glass barrel at a specific axial location relative to the syringe holder. The standard syringe is generally supplied with a needle cover 17 which is normally nearly equal in diameter to the largest diameter of the glass barrel (see Figure 10). The needle cover 17 can be rigid, but not necessarily. Within the needle cover 17, the needle is pricked or stuck within a needle sleeve 16, which may be made of rubber. If the syringe is inserted into the syringe holder with the needle first (or rather with the needle cover first), any inwardly directed gripping means will dirty the needle cover (or the needle cover if there is no needle cover). needle) when trying to pass. There is also the risk that the needle will be damaged during assembly, for example if it is pushed into any inwardly directed gripping means. Such damage to the needle is highly undesirable as it could cause injury to the patient or could affect or impede drug delivery, in particular as it is often not easily detected whether the needle is concealed within a needle cover and / or a rubber needle cover. Damage to the needle may only become apparent during the delivery of the medication. The consequent effect of a damaged needle on drug delivery may not be apparent to the patient.

This problem is solved by the use of a syringe holder 100 as illustrated in Figures 7 and 8. The syringe holder 100 comprises an elongated rear portion 102 in which there are viewing windows 103 so that the medication chamber in the barrel of a syringe held there would be visible. There is a barrel seat 101 (equivalent to the barrel seat 91 in the prior art device) at the rear end of the rear portion 102, but in practice it is not intended to abut the rim 90 of the syringe barrel. (unlike the prior art device).

The syringe holder also has an intermediate portion 105 of comparable diameter to the rear portion, and a front portion 106 of narrower diameter. The intermediate portion 105 is provided with a discontinuous annular rim 104. Together, the middle and front portions 105, 106 include radially spaced grooves 107 defining a plurality of radially flexible fingers 108. In the illustrated embodiment, there are three flexible fingers 108, but four or some other number of fingers may be provided. Figure 22 shows an embodiment in which four flexible fingers 108 are provided on the syringe holder 100. Each of the four fingers is necessarily thinner than those of the three-finger embodiment.

A typical example of a needle cover 17 is shown in Figure 22 (illustrated without the rest of the syringe for simplicity). The needle cover has a groove 17A inside it. If the syringe holder 100 is properly aligned with the needle cover of a syringe clamped therein, there is a possibility that one of the relatively thin flexible fingers 108 may undesirably catch or fall into the slot 17A, possibly causing damage to the needle. underlying that do not become apparent until an injection is given. This disadvantage can be overcome by ensuring that each of the flexible fingers 108 is preferably wider than the slot in the needle cover 17A, as illustrated in the three-finger embodiment of Figure 7.

As shown in Figure 8, gripping means 109 are provided on the inside of the flexible fingers 108 in the intermediate section 105, preferably in the form of an inwardly directed discontinuous annular protrusion. Referring to Figure 9, when a syringe is located within the syringe holder 100, the gripping means 109 abuts the front shoulder 92 of the barrel to define the axial position of the barrel relative to the syringe bracket.

The term "gripping means" is not limited to means that grips radially inward on the cylinder, although in some embodiments they may. More important is the fact that gripping means 109 (or equivalent) supports the syringe in a desired axial location and provides a reaction surface for the syringe so that the barrel will remain in compression during drug delivery.

As can be seen in Figures 10 and 11, the needle cover 17 has a diameter greater than the diameter normally available in the gripping means 109. In other words, the internal diameter between the gripping means 109 is less than the external diameter of the needle cover 17. However, as will be explained in more detail below, when the syringe is inserted into the syringe holder, when the needle cover 17 passes through the gripping means 109, the flexible fingers 108 flex radially outward to create a diameter sufficient for the needle cover to pass through the inwardly projecting gripping means, without exerting excessive force on the needle within it, thus minimizing the risk of damaging the needle. Once the needle cover has passed, the flexible fingers 108 return to their normal position (having an internal diameter smaller than the external diameter of the needle cover) and the gripping means 109 is located on the front shoulder 92 of the barrel to provide the reaction surface against which the syringe will remain compressed during drug delivery. In this position, the gripping means 109 is located axially between the needle cover and the front shoulder of the cylinder.

The front portion 106 of the syringe holder 100 is provided with a plurality of (preferably two) equidistant labels 110, the purpose of which will be described later below.

The simplest way to assemble the syringe and injection device is in a three-stage procedure, namely:

1. insert the syringe into the syringe holder, until the gripping means 109 is located on the front shoulder 92 of the barrel;

2. insert the syringe and syringe holder into the front of the injection device;

3. Assemble from the front to the rear of the injection device.

Compared to the two-stage assembly procedure of the prior art device, the additional assembly step is disadvantageous, but initially seems necessary as it is not obvious how steps 1 and 2 could easily be combined so that the syringe holder can be combined. can supply already assembled with the front of the device. This is because, once assembled at the front of the device, the flexible fingers 108 would be prevented from flexing radially outward due to their necessarily closed bearing with the front housing, thus preventing the insertion of the syringe and the cover. needle.

Therefore, in a further embodiment of the invention, a modified front housing for the injection device is provided that allows a two-stage assembly procedure to be used.

The modified front housing 200 (analogous to the nozzle 11 in the prior art) is illustrated in Figure 12. The front housing 200 has a hole 201, of sufficient diameter to allow passage of the needle 10, the cover 17 and the front and middle portions 105, 106 of the syringe holder (but not the flange 104).

The inner surface of the hole 201 is provided with two (or more) equidistant longitudinal grooves 202, each with a rear section 203 with a tapered surface providing a variable depth and a front section 204 of substantially constant depth. The boundary between the front and rear sections of each slot 202 is defined by a passage 205.

The slots 202 are positioned so that they can be aligned with the labels 110 on the front portion of the syringe holder.

The slots 202 allow the syringe holder 100 to be assembled into the front housing 200 at a specific axial position (relative to the front housing) so that the flexible fingers 108 are spaced from the front housing rather than encircling them.

The slots 202 also provide a radial location for the syringe holder 100 when inserted therein.

Figure 14 shows a modified end cap 300 (analogous to end cap 15 in the prior art) designed for use with the modified front housing 200 and how the syringe holder 100 is inserted into the front housing 200. The front casing 200 is inserted into the end cap 300 so that its front surface 206 abuts the inside of the end cap, so that no further forward movement of the front casing within the end cap is possible. extreme.

The narrow stop of the end cap 300, the front housing 200 and the syringe holder 100 means that, if present, the needle cover 17 is securely retained in position so that the risk of spillage is minimized. needle cover is accidentally loosened or detached. thus minimizing the possible loss of seal integrity between the rubber needle cover and the needle, which would otherwise compromise the sterility of the drug contained within the syringe. The carefully designed interaction between the components avoids the risk that, during assembly, the syringe holder 100 could undesirably "break" between the front end of the syringe barrel and the rear of the needle cover in such a way as to compromise the seal between the end of the needle and the needle cover in which it is punctured.

The end cap has a vertical ring 301 that protrudes and fits snugly into the hole 201 of the front housing 200. The vertical ring 301 has two evenly spaced projections on the outer surface thereof that are located in the longitudinal grooves 202 when the end cap and front housing are assembled together. Once assembled together, the vertical end cap ring and passage 205 together define a space 302 in which the labels 110 can be located on the syringe holder 100.

To insert the syringe holder 100 into the front housing 200, the labels 110 are aligned and pushed into the slots 202 until the labels 110 "click" on the passage 205 and are located in the space 302. This is the position. illustrated in Figures 14 and 15. Syringe holder 100 is now conveniently located axially so that gripping means 109 and flexible fingers 108 are not restricted within front housing 200 and end cap 300. The front housing, end cap and syringe holder are supplied in this ready-to-use state, along with the back of the injection device already assembled, for final assembly with a pre-filled syringe.

Therefore, it is a simple two-step procedure to finally assemble the syringe on the device, namely:

1. insert the syringe into the assembled front housing, end cap and syringe holder until the gripping means 109 is located on the front shoulder 92 of the barrel (as shown in Figure 16);

2. Assemble the front part to the back part already assembled of the injection device (not illustrated).

Figures 4-6 show the fully assembled injection device that includes the syringe holder 100. With reference to Figure 5, it can be seen that (unlike the prior art device) the rim 90 of the barrel does not make contact with the seat 101 of the barrel of the syringe holder 100, there is a space G between them. This is the result of the relative axial positions of the syringe holder and the syringe being determined at the front end, by the gripping means 109 and the front shoulder 92 and means that no undesirable stress is applied to the glass barrel during supply of medicine.

An alternative embodiment of the syringe holder is illustrated in Figures 17-20. Wherever possible, the same reference numerals that were used in connection with Figures 8-9 are used to identify similar components of the alternative embodiment. Note that Figures 17-20 show the front end of the device on the left side of the Figures, while Figures 8-9 show the front end of the device on the right side of the Figures.

In the Figure 17 embodiment of the syringe holder 100 ', the radially flexible fingers 108' have their free ends extending in the forward direction (compare radially flexible fingers 108 in Figure 8 which have their free ends extending in the backward direction). The gripping means comprises heads 109 'directed inwardly at the end of the flexible fingers 108. As best seen in Figure 19, the enlarged heads 109 'are capable of gripping the cone 93 at the front of the syringe barrel. Cone 93 is the region where needle 10 is attached to the syringe barrel.

As shown in Figure 18, when a syringe is assembled with the syringe holder 100 ', the needle cover 17 (having a diameter comparable to the syringe barrel) causes the flexible fingers 108' to flex radially outward from such that the enlarged heads 109 'rest on the outside of the needle cover 17.

When the end cap 300 and needle cover 17 are axially removed in the direction of the arrow in Figure 18, the enlarged heads 109 'must move radially inward to contact the syringe cone 93 to grasp the front end of the cylinder to provide the compression force during injection. However, if the flexible fingers 108 'are made of plastic and if the device is stored in the configuration of Figure 18 for many months before use (both are likely), the fingers 108' may no longer flex automatically. correctly inward when removing the needle cover 17.

Therefore, a spring retainer 111 is provided. The spring retainer 111 is made of steel, other metal, or other material that does not significantly lose its elasticity over time. The spring retainer has elongated fingers that cooperate with the flexible fingers 108 'to push them radially inward. Once the needle cover 17 has been removed, the spring retainer 111 pushes the enlarged heads 109 'into firm contact with the syringe cone 93, even if the flexible fingers 108' are no longer capable of doing so. This position is illustrated in Figures 19 and 20.

As illustrated in Figure 21, the gripping means (109 or 109 ') could alternatively be provided in the form of a clip 112, inserted axially into a slot 113 in the syringe holder to engage the front of the barrel. .

Other means may be envisaged to provide a reaction surface for the front of the barrel to provide a compressive force during injection, for example, a tapered elastomeric bushing that could snap into place once the needle cover has passed during injection. Assemble. It may be possible to grasp the forwardmost part of the cone, where the needle enters the cone, instead of grasping the outside of the cone. Alternatively, other means may be contemplated for gripping the front shoulder of the cylinder or the exterior of the cone.

It is noted that the viewing windows 103, 103 ', in the syringe holder are openings that create a space through which the glass fragments could move in case of breakage. If a break occurs, it is highly desirable to contain any glass shards to minimize the risk of injury. Thus, in an alternative embodiment (not illustrated), the viewing window openings are replaced with a solid but transparent or partially transparent material that still allows the user to see the inside of the syringe. Any of the openings 103, 103 'can be "filled" with a transparent material to form a window in the most conventional sense of the word; alternatively, all part of the syringe holder can be made of transparent or partially transparent material.

The reader's attention is directed to all papers and documents that are filed at the same time or before this specification in connection with this application and that are open to public inspection with this specification.

Each feature disclosed in this specification (including the claims, abstract and accompanying drawings), may be superseded by alternative features that serve the same, equivalent, or similar purpose, unless expressly stated otherwise. Therefore, unless expressly stated otherwise, each disclosed feature is just one example of a generic set of equivalent or similar features.

The invention is not limited to the details of any of the above embodiments. The invention extends to any novelty, or any novel combination, of the features disclosed in this specification (including the accompanying claims, summaries, and drawings), or any novelty, or novel combination, of the steps of any method or process thus disclosed. .

Claims (21)

1. An autoinjector comprising a housing in which a syringe can be mounted comprising: a cylinder to hold a volume of medication, a needle (10) at one end of the cylinder in fluid communication with the medication, an axially movable plunger in the cylinder to a forward most position; a needle sheath (16) that is capable of sealing the forward most end of the needle to maintain the sterility of the medication within the cylinder whereby, in use, the needle sheath must be removed from the needle immediately prior to actuating the autoinjector; Y a removable needle cover (17) for containing the needle cover (16); the autoinjector comprises: a syringe support means (100, 100 ') for supporting the syringe barrel at an axial location at or ahead of the forward most position of the syringe plunger, the syringe support means (100, 100') provides a reaction surface (109, 109 ') for a forward shoulder of the barrel or a narrow cone region of the syringe where the needle is attached; characterized in that said syringe support means (100, 100 ') comprises an intermediate portion (105) and a front portion which together include radially spaced grooves (107) defining a plurality of radially flexible fingers (108, 108'), the The plurality of radially flexible fingers (108, 108 ') comprise one or more inwardly directed protrusions that form said reaction surface, wherein the reaction surface (109, 109') is configured to provide an axial compressive force on the syringe barrel when a forward axial force is applied to the syringe plunger, and wherein when the syringe is inserted into the syringe support means (100, 100 '), the fingers (108, 108') radially Flexible flexes flex radially outward from a normal position as a needle cover (17) passes and then the spring returns to its normal position. The autoinjector of claim 1 wherein said autoinjector is a single use autoinjector. The autoinjector of any claim 1 or 2, configured such that the syringe is axially movable in said housing and is inclined such that the needle (10) is completely within said housing, wherein prior to injection the syringe it can be moved axially in order to move at least a part of said needle out of the housing and wherein after injection, the syringe is capable of retracting in order to retract said part of said needle into the housing. The autoinjector of any preceding claim wherein, in use, said reaction surface (109, 109 ') provides an axial compressive force to the front shoulder (92) or front cone (93) of the cylinder of the syringe. The autoinjector of any preceding claim wherein said inwardly directed protrusions are on the end of one or more radially flexible fingers (108, 108 ') and preferably comprise an enlarged inwardly directed head on the or each finger. (108) radially flexible. The autoinjector of any of the preceding claims wherein an internal diameter between said inwardly directed protrusions is smaller than the external diameter of the syringe barrel, and preferably wherein, when the device is fully assembled and ready for use, said inwardly directed protrusions are located axially between a needle cover (17) and the forward shoulder (92) of the syringe barrel. The autoinjector of any preceding claim wherein said syringe support means (100, 100 ') includes one or more viewing windows (103, 103'), to allow a user to view the barrel of a syringe supported therein, the viewing windows preferably comprise one or more openings in the syringe support means or a transparent or partially transparent portion of the syringe support means. The autoinjector of any preceding claim wherein said syringe support means (100, 100 ') further comprises one or more alignment labels (110, 110') at the forward end thereof, the autoinjector preferably comprising Additionally a front housing (200) having a hole (201) through it, the inner surface of the hole is provided with one or more longitudinal grooves (202), positioned such that said labels (110, 100 ') of alignment may be located therein, when said front housing (200) and syringe support means (100, 100 ') are assembled together. The autoinjector of claim 8 wherein the or each longitudinal slot (202) comprises a rear section (203) having a forward increasing depth and a front section (204) having substantially constant depth, and preferably at whereby a boundary between the rear and front sections is defined by a pitch (205). The autoinjector of claim 9 further comprises an end cap (300) having internal protrusions (301) therein that protrude into the longitudinal grooves (202) in the bore of the front housing (200), when assembled. seals said end cap and said front housing, such that a space (302) is defined between said internal protrusions in the end cap and said passage (205) in the front housing and, preferably, in which the labels ( 110, 110 ') alignment of the syringe support means (100, 100') are located in said space (302) defined to determine the axial location of the syringe support means (100, 100 ') with respect to said housing front and further and preferably wherein said syringe support means (100, 100 ') includes a radially extending rim (104, 104') of greater diameter than the internal diameter of said front housing (200). The autoinjector of any of the preceding claims, wherein the needle cover (17) and said needle sheath (16) are larger in diameter than the internal diameter between said radially flexible fingers (108, 108 ') to pass thereby during assembly of a syringe in said autoinjector. The autoinjector of claim 11 when dependent on claim 10 wherein said axial location of the syringe support means (100, 100 ') with respect to the front housing is such that said fingers (108, 108') radially The hoses are not confined within said front housing (200) and are free to flex radially when the front housing and syringe support means are assembled together and prior to mounting a rear partial assembly of the autoinjector therein. The autoinjector as claimed in any of the preceding claims, wherein a syringe is mounted comprising: a cylinder to hold a volume of medicine, a needle (10) at one end of the barrel in fluid communication with said drug; Y an axially movable plunger in the cylinder to a more forward position. The autoinjector of claim 13 wherein said syringe comprises a needle sleeve (16) that substantially covers said needle (10) to protect the needle from mechanical damage and preferably completely covers said needle (10) and is sealed against the syringe to maintain the sterility of the outer surface of the needle (10). The autoinjector of claim 14 wherein said needle sleeve (16) comprises a solid elastomeric material into which the needle (10) is embedded and, preferably, wherein said needle sleeve (16) is contained within of a needle cover (17). 16. The autoinjector of claim 15, wherein said radially flexible fingers (108) are configured to flex outward enough to allow the needle cover (17), said needle sleeve (16) of greater diameter than the diameter internal between said radially flexible fingers (108, 108 ') to thereby pass during mounting of a syringe in said autoinjector. The autoinjector of claim 15 or 16 wherein the lip (90) of the syringe barrel finger does not contact the syringe support means (100, 100 ') during drug delivery. The autoinjector of claim 16 wherein, when the autoinjector is fully assembled ready for use, said inwardly directed protrusions (109, 109 ') closely support the needle cover (17) and / or said sheath (16) to reduce the risk of said needle sleeve loosening or detaching from the needle (10), potentially compromising the sterility of the needle. The autoinjector of any of claims 13 to 18 wherein said syringe support means (100, 100 ') is generally cylindrical and of a diameter less than the diameter of the rim (90) of the syringe barrel finger. such that the syringe support means is sized to closely surround the barrel of the syringe. 20. The autoinjector of any of claims 13 to 19 wherein the housing is an outer housing and at least part of the needle is axially movable in and out of said outer housing, but is tilted to be completely within said housing, the autoinjector further comprises: an inner casing between the outer casing and the cylinder and plunger; Y a power source in communication with said internal casing, in which the inner shell can be moved by the power source between three positions, namely: a first position in which the inner casing is in communication with the cylinder such that, in use, the plunger and the cylinder can be moved axially in order to move at least part of said needle out of the outer casing; a second position in which the inner housing is in communication with the plunger, but not with the barrel such that, in use, said plunger can move axially in said barrel in order to eject medication through the needle; Y a third position in which the inner casing is not in communication with the plunger or the cylinder such that, in use, the plunger and cylinder are capable of retracting in order to retract the needle into the outer casing. 21. A method of assembling the autoinjector of any of the preceding claims comprising the steps of: providing a first partial assembly comprising a syringe support means (100, 100 '), the syringe support means (100, 100') providing a reaction surface (109, 109 ') for a leading shoulder of a cylinder or a narrow cone region of a syringe where a needle, a front housing (200) and a tightly fitting end cap (300) are attached, wherein said syringe support means (100, 100 ') comprises an intermediate portion (105) and a front portion (106) which together include radially spaced grooves (107) defining a plurality of radially flexible fingers (108, 108 '), the plurality of radially flexible fingers (108, 108') comprise one or more inwardly directed protrusions forming said reaction surface; and providing a second assembly comprising a rear portion of the autoinjector; providing a syringe comprising a barrel for containing a volume of medicine, a needle (10) at one end of the barrel; an axially movable plunger in the cylinder to a forward most position; and a removable needle cover (17) to contain a needle cover (16) that is capable of sealing the forward most end of the needle to maintain sterility of the drug within the barrel, whereby in use, the needle cover must be removed from the needle immediately before operating the autoinjector; inserting the syringe axially into the rear end of the first partial assembly until said syringe support means (100, 100 ') supports the syringe; Y assembling said first partial assembly and second assembly together such that said syringe support means supports the syringe in an axial location at or ahead of the most forward position of the plunger, whereby in use said surface (109, 109 ') reaction provides an axial compression force on said cylinder when a forward axial force is applied to the plunger; and wherein when the syringe is inserted into the syringe support means (100, 100 '), the radially flexible fingers (108, 108') flex radially outward from a normal position as the cover (17) passes needle and then the spring returns to its normal position.